Edinburgh's Geology - sites

There are many places of geological interest in and around Edinburgh.  An excellent guide to the area is 'Lothian Geology - an Excursion Guide' by McAdam & Clarkson, 1996.  Find out more about the book in the Publications pages. 

Listed below are some of the sites worth visiting.  If you have not already done so, but would like to read about the region's geological history, click here.

Arthur's Seat and Salisbury Crags
Edinburgh Castle Rock
Blackford Hill and the Hermitage of Braid
Corstorphine Hill
North Berwick
Catcraig/Barn's Ness

Pease Bay to Cove
Bathgate Hills - Petershill Quarry
National Museums of Scotland
Our Dynamic Earth
Newtongrange Mining Museum

Many of these sites, and several others in the Lothian area, have information leaflets published by the Lothian and Border GeoConservation Group, which is a committee of the Edinburgh Geological Society. For further information visit the GeoConservation publication pages.

Owing to their geological significance, many of the localities in this region are designated as Sites of Special Scientific Interest (SSSI) and as a result are protected by law.  The conservation and preservation of these sites is of paramount importance. Please respect and care for our geological and natural heritage. 

View of Arthur's SeatArthur's Seat and Salisbury Crags

Arthur's Seat and Salisbury Crags dominate the Edinburgh skyline, and a climb to the top of either offers a fantastic view across the city and beyond - the summit of Arthur's Seat is 251m (823 feet), and Salisbury Crags is 122m (400 feet).

Arthur's Seat is the remnant of a Lower Carboniferous (Dinantian) volcano.  Parts of the volcano were eroded due to glacial activity, but much of the internal structure of the volcano remains.  The hill exhibits lava flows, four vents (Edinburgh Castle Rock is a fifth vent), parts of the cone, ashes, agglomerates, sills, dykes and part of the overlying sedimentary sequence.

Salisbury Crags is a large sill that was emplaced long after the volcano became extinct.  Tilting of the local rock and erosion by glaciers has exposed the sill.  A path leads around the base of the sill, allowing the study of the rock.  At the south-eastern end of the sill lies Hutton's Section - the telling evidence for magmatic intrusion.  Other contacts with the local rock can be seen elsewhere on the crag.

Location: approximately 1km east of Edinburgh city centre
Note: hammering or removal of material from the site is NOT permitted

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Arthur's Seat image © Reproduced by the kind permission of the trustees of the National Museums of Scotland.

View of Edinburgh Castle (from Blackford Hill)Edinburgh Castle Rock

The imposing rock that the famous Edinburgh Castle was built on, is a plug formed from one of the vents of Arthur's Seat (see above).  The base of the plug can be studied on almost three sides, although steep grassy slopes prevent direct access to parts of it.  The rock is also famous for its 'partner' - the Royal Mile (or High Street).  The street slopes gently to the east, away from the Castle and leads to Holyrood Palace near the foot of Arthur's Seat. 

This whole feature is a crag-and-tail, formed during the last ice-age.  The glaciers, travelling from the west, were deflected around the hard volcanic rock, leaving uneroded soft sedimentary rock lying behind it.  Two shallow valleys lie to the north and south of the rock, gouged out from the deflected ice.  These are Princes Street Gardens and the Grassmarket and Cowgate.  The junction between the 'crag' and the 'tail' can be studied from Johnston Terrace, Princes Street Gardens and within Edinburgh Castle itself.

Location: Edinburgh city centre
Note: hammering is NOT permitted

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View of Blackford Hill and valley to the northBlackford Hill and the Hermitage of Braid

Blackford Hill is another good site to visit for views across the city and beyond, including a fantastic view of Aruthr's Seat and Salisbury Crags.  The summit lies at 164m (539 feet), although a car park lies adjacent to the Royal Observatory (access from Observatory Road), where it's a gentle 400m walk to the summit.

The hill is formed from Devonian andesitic and trachytic lava flows.  From the hill, the Pentland Hills to the south form the continuation of these volcanic rocks.  The hill is another crag-and-tail, with the gentle slopes to the east leading to the University of Edinburgh's King's Buildings campus.

To the northern and southern sides of the hill lie two shallow valleys gouged from the deflected ice.  To the north lies Blackford Pond, and to the south lies the Hermitage of Braid (offering one of the most peaceful walks within the city).  A walk along the Braid Burn leads to Agassiz Rock, the site where in 1840, Louis Agassiz found evidence for the erosive action of ice in Scotland.

Location: approximately 3km south of Edinburgh city centre

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Corstorphine Hill

Corstorphine Hill is a (mostly) wooded ridge with its summit lying at 161m (531 feet).  Many paths criss-cross the hill, allowing for a look at the rocks as well as offering peaceful walks and views across Edinburgh and beyond.  The hill offers the study of Carboniferous sedimentary rocks (sandstone and flagstone) and the dolerite sill that was emplaced between the sedimentary layers, also during the Carboniferous.

This is another of Edinburgh's a crag-and-tails.  Tilting of the local rock and the subsequent erosion of the overlying sedimentary rocks by glaciers during the last ice age, have exposed the sill on the western slopes (the crag), and the underlying sedimentary rocks on the eastern slopes (the tail). The dolerite on the western slopes exhibit excellent glacial striations.

Location: approximately 4km west of Edinburgh city centre (behind Edinburgh Zoo)

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North Berwick

The coastline that stretches eastwards from North Berwick harbour, round towards Tantallon Castle marks the location of a series of Dinantian (Lower Carboniferous) tuff and agglomerate-filled volcanic vents.  Most of these vents are partially exposed on the foreshore, with the agglomerates typically containing red and/or green tuffs.  Basaltic red and green tuffs are also commonly seen outwith the vents. 

Several islands are visible from the shore.  These are all igneous in origin, with the largest island being the Bass Rock.  This is a volcanic plug composed of phonolite, and like many other volcanic plugs in the region, has been resistant to the ravages of glacial erosion.  The rock, once a prison, is famous as a home for gannets.  Boat trips sail to the islands from North Berwick, though you will not be able to land on them.

North Berwick Law lies just south of North Berwick town.  It is the dominant landmark in the area (accessed from the B1347), and is clearly visible from parts of Edinburgh.  It is a conical shaped volcanic plug, composed of phonolitic trachyte.  It has also resisted glacial erosion which has resulted in the formation of a crag-and-tail.  It's a steep climb to the top, but it offers superb views across the Lothians, Fife and beyond.

Location: approximately 32km east of Edinburgh city centre (approx. 45 mins drive)
Note: beware of the tides

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Catcraig/Barn's Ness

This coastal section offers the best fossil collecting locality in the area, however collecting fossils from in-situ is not permitted.  The rocks expose mainly the Dinantian (Lower Carboniferous) Lower Limestone Group.  This group is a cyclical sequence of thin coal seams and seatearths, thick fossiliferous limestone and calcareous mudstones, and deltaic mud/silt/sandstones.  In the 18th century the limestones were quarried and burnt for agricultural lime - you can see the limekiln on the coastal path.  Today, the limestone is quarried for use by the cement works that lies just to the north.

On the foreshore, crinoids, brachiopods, bivalves, corals (Lithostrotion and Koninckophyllum), Stigmaria, trilobites and trace fossils can be found in varying degrees of abundance.  A thin coal seam can be seen in the low cliff that runs parallel to the shore.  Running across the foreshore, what at first appears to be an igneous dyke standing proud is actually a dolomitised fault zone.

Location: approximately 27km east of Edinburgh city centre (approx. 45 mins drive)
Note: only collect fossils from loose material - hammering is NOT permitted

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Photograph of Pease BayPease Bay to Cove

This coastal section allows you to cross a conformable succession from Upper Old Red Sandstone (Upper Devonian) desert/fluviatile sandstones into Lower Carboniferous sediments.  The Upper Old Red Sandstone sequence at Pease Bay consists generally of red fluviatile sandstones and flood plain deposits.  Cornstone nodules are also seen, formed as a result of caliche soil formation.

The Devonian - Carboniferous conformity is found on the headland to the north of Pease Bay.  Here, the base of the Carboniferous is taken as a cementstone horizon with conglomeratic layers containing dolomitic clasts and fish scales and spines.  Continuing north towards Cove and up through the Carboniferous sequence, siltstones, sandstones and shales are found, exhibiting excellent sedimentary structures, including climbing ripples, slump structures and cross-stratification.  There is a cyclical horizon of coals, seatclays and sandstones, and further up the section (beyond Cove Harbour), a thin oil-shale horizon can be traced along the shore. 

Fossils can be found on this section.  Fish remains are rare, but plant remains and other marine fauna including bivalves, brachiopods and crinoids (ossicles) are more common, especially in Cove Harbour.

Location: approximately 30km east-southeast of Edinburgh city centre (approx. 1 hour drive)

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Bathgate Hills - Petershill Quarry

The Bathgate Hills consist mainly of basaltic volcanic rocks, but interspersed with these are marine and freshwater limestones.  Two important sites exist here: East Kirkton Quarry and Petershill Quarry.  The rocks at East Kirkton are freshwater in origin, but are thought to also have been associated with hot-springs.  During the 1980's this site was extensively excavated by the National Museums of Scotland, leading to the discovery of many important fossils including amphibians and insects.  However today, there is little to see at the site, other than the sedimentary sequence in the small quarry face.

However, Petershill Quarry is more worthy of a visit.  The site exhibits the Petershill Limestone - a very fossiliferous lithology.  It contains abundant solitary and colonial corals.  Other fossils include brachiopods, crinoids and other echinoids.  The succession on the southern wall of the quarry grades from a lithology with low diversity fauna (productid-fenestellid), through a high diversity fauna (productid-sponge-rostroconch), to an echinoid dominated lithology at the top.

Location: approximately 18km west of Edinburgh city centre (approx. 30 mins drive)
Note: hammering is NOT permitted

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The National Museums of Scotland

The National Museums of Scotland houses Scotland's largest collection of geological specimens.  Visit the Earth Science galleries in the Royal Museum and the Beginnings gallery of the Museum of Scotland to see fossils, minerals, rocks and structures from Scotland and around the world.

Location: Chambers Street, Edinburgh
Admission: Free
Information: (0131) 247 4219

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Our Dynamic Earth

Our Dynamic Earth shows you the Earth's dramatic story.  Begin in the present day and journey 15,000 million years back through time to the Big Bang.  Experience erupting volcanoes and earthquakes. Fly over glaciers to learn how Scotland's landscape was formed during recent ice ages.  Follow the evolution of life from the beginning, before exploring the oceans and Polar Regions and watching the downpour in the tropical rainforest, before finally lying back to find your place on the planet in the Showdome. 

Location: Holyrood Road, Edinburgh (at the foot of Arthur's Seat)
Information: (0131) 550 7800

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Newtongrange Mining Museum

Scotland's Black Diamonds tells the story of the mining industry's history.  This Five-star attraction will take you on a trip through the highs and lows of an industry once the backbone of Scotland.  See inside the wonderfully restored Lady Victoria Colliery, where a guided tour will combine mining artefacts with innovative interactive activities.  Visitors can see, hear and feel the many elements of this dangerous and potentially deadly environment.

Location: Newtongrange (15km south of Edinburgh on the A7)
Contact: (0131) 663 7519

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Are you planning to visit Edinburgh or the Lothians?

Need reference material - visit the British Geological Survey on-line shop

Looking for a good bookshop whilst in Edinburgh, try:

    Blackwells, 53 South Bridge.  (0131) 556 6743

    the British Geological Survey shop, Murchison House, West Mains Road. (0131) 667 1000

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